The use of linear fire extinguishers in the form of a high strength, elongated tube containing a pressurized fire extinguishant such as Halon 1301 has been suggested both in U.S. Pat. Nos. 4,854,389 (the '389 patent) and 4,938,293 (the '293 patent), both assigned to the present assignee and both including the present inventor as one of the co-inventors. Here, a flexible linear shaped charge (FLSC) is placed parallel to the axis of the tubular container in close proximity to the container and when detonated cuts the tube to allow for distribution of the fire extinguishant in a very short period of time, e.g., 2 milliseconds. The installation is typically in the dry bay of a military aircraft wing to rapidly extinguish fires due to, for example, a punctured fuel tank. It may also be used in the ullage (empty space) of a fuel cell to prevent overpressures (due to fires, etc.) which would cause structural damage.
As discussed in the '293 patent in order to provide a net reaction force of substantially zero on the tubular container when activated, and thus to minimize stress on the air frame, it has been proposed that a single container be cut on opposed sides simultaneously. This is illustrated in FIG. 3 where container 17 has the opposed shaped linear charges 33a and 33b located at the interior of the container, diametrically opposed, along the diameter 18. When the shaped charges are detonated they cut along the lines 31a and 31b which are elements of the cylindrical container 17 and substantially equal opposite reaction forces F1 and F2 are produced which effectively nullify the reaction forces. As illustrated, however, the tube 17 when cut may produce fragments.